 You can now provide types for CSS variables. Byte for byte checks are now performed for service worker scripts imported by import scripts. And I've got details for two new origin trials that provide some neat new functionality. I'm Pete LaPage. Let's dive in and see what's new for developers in Chrome 78. CSS variables technically called custom properties are awesome. They let you define and use your own properties throughout your CSS. But custom properties are not much more than a simple search and replace. If you used a variable for a color, but assigned a URL as the value, the rule would just be silently discarded. With CSS properties and values API, you can define a type and a default fallback value for your custom properties. Registering a property is as easy as calling window.css.register property and providing the name of the property you're defining, the type of property it is, if it should inherit, and its initial value. Take a look at Sam's article on web.dev, linked in the description for complete details. Byte for byte checks are now performed for service worker scripts imported by import scripts. In the past, the only way to force an installed service worker to pick up changes to an imported script was to change either the imported scripts URL usually either by adding a semver value or a hash in the URL. Starting in Chrome 78, each time an update check is performed for the top-level service worker file, Chrome will also check whether or not the contents of any imported scripts have changed. If it has, it will trigger the full service worker update flow. This brings Chrome into conformance with the spec and matches what both Firefox and Safari do. Jeff has all the details in his post on developers.google.com, including some important things to know about how the HTTP cache impacts the update cycle. Origin Trials provide an opportunity for us to validate experimental features and APIs, and make it possible for you to provide feedback on their usability and effectiveness in broader deployments. Experimental features are typically only available behind a flag. But when we offer an Origin Trial for feature, you can register for that Origin Trial to enable the feature for all the users on your Origin. Opting into an Origin Trial allows you to build demos and prototypes that your beta test users can try for the duration of the trial without requiring them to flip any special flags in Chrome. There's more info on Origin Trials in the Origin Trial guide for web developers. An Origin Trial for the new native file system API has just started. The native file system API enables you to build powerful web apps that interact with files on the user's local device. After a user has granted a web app access, the API allows web apps to read or save changes directly to files and folders on the user's device. I'm really excited about all the new experiences this enables. No more having to upload or download any file that I want to work with. Check out my post about the native file system API for all the details including code, a demo, and how we're working to keep users safe. The SMS receiver API now available as an Origin Trial lets your web app receive specially formatted SMS messages for your app's origin. From this, you can programmatically obtain an OTP from an SMS message and verify a phone number for the user more easily. AG has a great post on web.dev with all the details and how you can sign up for the Origin Trial. Don't forget to tune in to the Chrome Dev Summit on November 11th and 12th. It'll be streaming live right here on the Chrome Developers YouTube channel. All the details including docs and specs are in the updates post linked in the description. Be sure to check out the latest Chrome DevTools video to learn what's new in DevTools and don't forget to subscribe. I'm Pete LaPage and as soon as Chrome 79 is released, we'll be right here to tell you what's new in Chrome.